1. Technical Field
The present invention relates to vibration isolation systems, and more particularly, an assembly which isolates a gyroscope from mounting surface vibratory heat expansion, and/or contraction-induced rotational displacements.
2. Background Art
A wide variety of torque-producing devices make use of spinning rotor elements mounted on low-friction bearings. Among such devices are gyroscopes which have many applications in the aerospace industry. Gyroscopes are used, for example, in airplanes, torpedoes, and missiles as a basic element in automatic steering systems to "remember" the orientation of the horizon and the direction of north during maneuvers. Such torque-producing devices are generally mounted on a support structure. It has been found that for many applications, it is desirable to isolate the gyroscopes and the support structure from the vibrations and other extraneous dynamic motions of the base on which it is mounted so as to help reduce potential rotational discrepancies.
In many systems and devices in current use, it is desirable to isolate a support structure from vibrations as well as to help ensure that the support structure maintains a constant angular orientation with respect to a predetermined reference surface. For example, the support structure of an inertial navigation system often is mounted within a vehicle whose position is to be determined in such a manner that vibrations of the vehicle which may be transmitted to the support structure do not adversely affect gyro operation and also in such a manner that the support structure experiences no rotational movement with respect to the vehicle, or, in other words, the angular orientation of the support structure with respect to the vehicle is continually maintained. The isolating requirements of a support structure becomes clear when it is realized that the gyroscopes in the accelerometer which are mounted on the platform rectify high frequency vibration applied thereto so that an output signal is generated by these components in response to vibratory displacement whereby the accuracy of the navigational system is affected. Further, unless the angular orientation for the support structure is maintained, inaccurate rotation rates will be sensed, thereby severely limiting the accuracy of the system.
Several exemplary isolation and mounting assemblies are disclosed in U.S. Pat. Nos. 3,057,592 issued to Thrasher; U.S. Pat. No. 3,151,833 issued to Thrasher; U.S. Pat. No. 4,099,696 issued to Toome; U.S. Pat. No. 4,270,393 issued to Osborne et al; U.S. Pat. No. 4,531,701 issued to Treu; U.S. Pat. No. 4,618,111 issued to Sherwood et al; U.S. Pat. No. 4,688,909 issued to Smith; U.S. Pat. No. 4,771,644 issued to Meron; U.S. Pat. No. 4,890,812 issued to Chechile et al; and U.S. Pat. No. 5,138,903 issued to Grossenbacher, Jr., et al.